The present invention generally relates to the production of articles of manufacture in a computer simulation or in the real world, and more particularly, to a method for accurately evaluating pattern compliance for a simulated or manufactured article.
American, Canadian, German, and International Organization for Standardization (ISO) standards define methods for specifying multiple levels of feature related tolerances. However, the manufacturing industry does not have an efficient or effective way of determining whether or not the requirements are achieved. Furthermore, there is no means for accurately assessing the effects of computer simulations with respect to feature relating tolerances. Inspection data of manufactured articles and varied feature data in simulations are not currently evaluated in an automated and correct manner to determine whether or not combined feature parameters such as hole size and location are acceptable to the applied feature relating tolerances. Evaluation of manufactured or simulated hole size, form, orientation, and location are all completed separately, and confidence in the accuracy of each evaluation is low.
Referring to FIG. 1, one method for documenting inspection data consists of paper gaging where information is recorded on paper. Measurements are taken, and errors are plotted on a grid 94 at an enlarged scale using a true position 96 as the origin. Hole positions 92 are then plotted on the grid 94. Concentric circles 90 representing tolerance zone diameters are then overlain to determine positional errors. A problem with this method however, is that it is time consuming because it is not automated, nor is this method used with an automated process. Another problem is the difficulty of best fitting the concentric circles 90 into a position that encompasses all the hole positions 92 within the applicable concentric circle.
Another method for documenting inspection and simulation data uses variation analysis software that assesses feature related tolerances. Approximations and iterations are used that combine size, orientation, and location variations. Multiple iterations of inspecting feature size and positions are used to increase accuracy. However, using approximations reduces accuracy, and using multiple iterations causes excessive analysis time.
As can be seen, there is a need for accurately evaluating inspection and simulation data. Also, there is a need for evaluating inspection and simulation data in a timely manner, with perhaps, using only a single iteration. Moreover, there is a need for quickly analyzing inspection and simulation data in a step of the manufacturing process so that the results of the analysis can be used in subsequent processes.
Variation effects within a pattern of features may be determined when performing a variation analysis of a design prior to manufacturing that design. The variation analysis software performs hundreds or thousands of simulated build cycles, and in each cycle, varies all of the parameters randomly. Assembly variation analysis that utilizes feature patterns, such as holes, for assembly is currently reliant on approximations and iterations for the assembly of parts. Such a process may introduce error, is inefficient, and requires advanced software skills for completion.
In addition to the need for assessing produced parts, there is a need to accurately determine the variation effects on patterns of features during variation analysis.